When I taught at a charter school, I once gave out 37 demerits in a 50-minute period. This was the sort of achievement that earned a new teacher praise in faculty-wide emails at Achievement First Amistad High School, in New Haven, Conn.

Amistad is a No Excuses school, in the mold of high-profile charter networks such as KIPP and Success Academy. The programs are founded on the notion that there can be “no excuses” for the achievement gap between poor minorities and their more affluent, white counterparts. To bridge that gap, they set high expectations and strict behavioral codes. School days are long. Not a moment is to be wasted. Classes even rehearse passing out papers quickly so they can save every second for drilling academic content. Instruction is streamlined with methods that data says lead to strong performances on standardized tests, which lead to college acceptances.

In May, Amistad’s students decided they’d had enough of compliance. One morning, they refused to attend classes and instead marched to protest the school’s racism and draconian discipline system. In a way, they were taking after their school’s namesake: Nearly 200 years ago, the Amistad was a slave ship whose cargo rebelled, then demanded education as well as freedom.

Amistad’s students were mostly protesting the fact that their school doesn’t have more minority teachers: Achievement First says 17 percent of its faculty members at its five New Haven schools are black or Latino, which is roughly what I saw at Amistad. But the problem goes far beyond the racial composition of the faculty. More important, the students would benefit from teachers who treated them as equals in dignity and the pursuit of knowledge and wisdom.

The Achievement First network, like many No Excuses schools, hammers its students from their first days with the notion that each of them will graduate from college. To do so, they must work hard. At school, students encounter careful uniform checks and communal chanting of motivational slogans. And because students will face professional standards in college and the workplace, No Excuses schools insist that they start young. Posture and eye contact are important, even for 16-year-olds. Class is not to proceed without total compliance.

By some measures, the methods work. At Amistad, for example, 100 percent of graduates are accepted to college, many to very selective ones. And yet such charter schools have often been criticized as excessively harsh. A New York Times story last year described Success Academy students peeing their pants because they were not permitted to go to the bathroom during practice tests. That harshness looks worse when it is carried out mostly by white teachers against students who are overwhelmingly black and Hispanic.

On my first day teaching 10th-grade English, I broke with No Excuses protocol. I wanted my students to fall in love with ideas; I wanted them — not me, and certainly not some figure behind a desk at Achievement First headquarters — to control their own confrontation with difficult concepts. So I had them rearrange their desks into a circle and gave them a short but baffling text by Jorge Luis Borges. The kids struggled. More than a few of them broke the behavioral code (slouching, talking to classmates, shouting out their reactions to the reading or m my queries). But they worked hard and asked questions. At the end of the class, one student thanked me: “I’ve never thought about such big ideas before,” she said.

From that day, the school’s administration, which learned about the violation, had my number. An administrator watched my class every day. If I didn’t fully enforce the school’s code — under which demerits must be issued for slouching, looking at the wrong person or even taking notes when not explicitly directed to — the administrator would correct me on the spot.

Soon, questions were forbidden. In an email to the faculty, the school’s principal explained that the 10th grade was not doing well. Evidence included the fact that students were hugging each other in the halls. As a solution, the principal presented a rule: “There Are No Questions.” He explained: “Every time you engage with a question, you effectively A) go off your carefully planned lesson pacing, B) put one student over the rest of the class and C) kill momentum.”